Modeling of heavy metal salt solubility using the extended UNIQUAC model

Iliuta, Maria C.; Thomsen, Kaj; Rasmussen, Peter

doi:10.1002/aic.690481125

Cited by 31 publications

(12 citation statements)

References 86 publications

(1 reference statement)

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“…Figure 23 shows an application of Chen's model to aqueous organic electrolytes. A similar theory, based on the UNIQUAC equation, was presented by Iliuta et al (2002) who gave particular attention to solubilities of heavy-cation salts. Figure 24 shows calculated and observed solubilities of various hydrates of Zn(NO 3 ) 2 .…”

Section: Electrolyte Solutionsmentioning

confidence: 43%

“…In addition to the anhydrous salt, five hydrates are formed in the solution containing zinc nitrate: nonahydrate, hexahydrate, tetrahydrate, dihydrate, and monohydrate. Calculations using a g E model that combines UNIQUAC with the Debye-Huckel theory are able to describe the five eutectic points and one peritectic point (P) of the aqueous Zn(NO 3 ) 2 system (from Iliuta et al, 2002).…”

Section: Electrolyte Solutionsmentioning

confidence: 46%

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Thermodynamics of fluid‐phase equilibria for standard chemical engineering operations

2004

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Section: Electrolyte Solutionsmentioning

confidence: 43%

Section: Electrolyte Solutionsmentioning

confidence: 46%

Thermodynamics of fluid‐phase equilibria for standard chemical engineering operations

2004

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“…It seems more than likely that the conclusions drawn here apply also to other less-often-used, semi-empirical electrolyte models such as eNRTL (Song and Chen, 2009), MSA (Triolo et al, 1976), MSA-NRTL (Papaiconomou et al, 2002), UNIQUAC (Iliuta et al, 2002) or the 'mixed solvent electrolyte model' (MSE) implemented by OLI (Wang et al, 2002(Wang et al, , 2004. The temptation to improve the fitting of thermodynamic property models by repeatedly introducing new variants with systemspecific basis functions and additional adjustable parameters is not confined to the Pitzer equations (e.g., see Partanen, 2012).…”

Section: Discussionmentioning

confidence: 43%

Aqueous electrolyte solution modelling: Some limitations of the Pitzer equations

Rowland

Königsberger

Hefter

et al. 2015

Applied Geochemistry

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Despite intense efforts, general thermodynamic modelling of aqueous electrolyte solutions still presents a difficult challenge, with no obvious method of choice. Even though the Pitzer equations seemingly provide a well-established theoretical framework applicable to many chemical systems over a wide range of temperatures and pressures, they are not as widely adopted as their early promise might have suggested. This is strikingly illustrated by the simultaneous appearance in the literature of numerous, different (and potentially incompatible) Pitzer models alongside a proliferation of alternative theoretical approaches with inferior capabilities.To better understand this problem, the ability of the Pitzer equations to represent the physicochemical properties of aqueous solutions has been systematically investigated for exemplar electrolyte systems. Pitzer ion-interaction parameters have been calculated for selected systems by least-squares regression analysis of published solution data for activity coefficients, osmotic coefficients, relative enthalpies, heat capacities, volumes and densities to high temperatures and pressures. Although satisfactory fits can be achieved when the ranges of conditions are carefully chosen and when sufficient data are available to constrain the regression, the fits obtained tend otherwise to be unsatisfactory. The Pitzer equations do not cope well with gaps and other deficiencies in the regressed data. Profound difficulties, poorly recognized hitherto, can also arise because of variation in the sensitivity of the Pitzer functions to values for different physicochemical properties when these are combined. Given the dimensionality of numerous related thermodynamic properties, all changing as functions of composition, temperature and pressure, these problems are difficult to detect, let alone address, especially in multicomponent systems. The growing practice of improving fits simply by adding basis functions (thereby increasing the number of adjustable parameters) should be deprecated because it increases the likelihood of error propagation, introduces subjectivity, makes independent verification difficult and has deleterious implications for both automated data processing and for consistency between thermodynamic models.

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“…Recent attempts to extend UNIQUAC and UNIFAC to model electrolyte solutions are less than satisfactory (Iliuta et al, 2002). Proper molecular insights and theoretical rigor are yet to be structured into the UNIQUAC/UNIFAC equations to account for the presence of ions.…”

Section: Achievements In Modeling Electrolyte Systemscontrasting

confidence: 41%

Industrial perspective

Beach¹

Solidification and Casting

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The use of advanced modeling and simulation tools for both design and operations has long since become routine in industry, and their development has been well documented at previous FOCAPD meetings. Nevertheless many long-existent needs and new requirements are not met, and both the enabling technologies and application of these tools continues to evolve. This paper provides an industrial perspective on the current state of modeling and simulation technology, with an emphasis on recent developments, emerging technologies, and new industrial applications that promise to have a significant impact on industrial practice and economic effectiveness, as well as gaps requiring further research. Three main subject areas are covered. The first is physical property modeling, the technology for representing the properties and phase behavior of material. The second is systems and architectures for modeling and simulation. The third is design environments that enable effective use of models.

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Modeling of heavy metal salt solubility using the extended UNIQUAC model

Cited by 31 publications

References 86 publications

Thermodynamics of fluid‐phase equilibria for standard chemical engineering operations

Thermodynamics of fluid‐phase equilibria for standard chemical engineering operations

Aqueous electrolyte solution modelling: Some limitations of the Pitzer equations

Industrial perspective

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